In the following discussion certain articles and methods will be described for background and introductory purposes. Nothing contained herein is to be construed as an “admission” of prior art. Applicant expressly reserves the right to demonstrate, where appropriate, that the articles and methods referenced herein do not constitute prior art under the applicable statutory provisions.
Catheters, particularly intravascualar (IV) catheters, are used for infusing fluid, such as normal saline solution, various medicaments and total paternal nutrition, into a patient, withdrawing blood from a patient or monitoring various parameters of the patient's vascular system. Peripheral IV catheters tend to be relatively short, and typically are on the order of about two inches or less in length. The most common type of IV catheter is an over-the-needle peripheral IV catheter. As its name implies, an over-the-needle catheter is mounted over an introducer needle having a sharp distal tip. At least the distal portion of the catheter tightly engages the outer surface of the needle to prevent peelback of the catheter, thereby facilitating insertion of the catheter into the blood vessel. The catheter and the introducer needle are assembled so that the distal tip of the introducer needle extends beyond the distal tip of the catheter, with the bevel of the needle facing up away from the patient's skin.
The catheter and introducer needle assembly is inserted at a shallow angle through the patient's skin into a blood vessel. There are many techniques for inserting such a catheter and introducer needle assembly into a patient. In one insertion technique, the introducer needle and catheter are inserted completely into the blood vessel together. In another technique, the introducer needle is partially withdrawn into the catheter after the initial insertion into the blood vessel. The catheter is then threaded over the needle and inserted completely into the blood vessel.
To verify proper placement of the catheter in the blood vessel, the clinician confirms that there is flashback of blood in a flashback chamber. The flashback chamber is typically formed as part of the needle hub. Alternatively, where the introducer needle includes a notch, i.e., a hole or opening in the sidewall of the introducer needle, flashback of blood can be observed in the annular space between the introducer needle and the catheter, in the catheter adapter and, where the catheter is an integrated catheter, in an extension tube extending from a side arm formed in the catheter adapter. Once proper placement of the catheter into the blood vessel is confirmed, the clinician applies pressure to the blood vessel by pressing down on the patient's skin over the blood vessel distal to the introducer needle and catheter. This finger pressure occludes, or at least minimizes, further blood flow through the introducer needle and the catheter. The clinician then withdraws the introducer needle, leaving the catheter in place, and attaches an appropriate device to the catheter. Such a device can include a fluid delivery device, a PRN, a deadender cap or a blood pressure monitoring probe. Once the introducer needle is withdrawn from the catheter, the introducer needle is a “blood contaminated sharp” and must be properly handled.
In recent years, there has been great concern over the contamination of clinicians with a patient's blood and a recognition that blood contaminated sharps must be disposed of to avoid an accidental needle stick. This concern has arisen because of the advent of currently incurable and fatal diseases, such as Acquired Immune Deficiency Syndrome (“AIDS”), which can be transmitted by the exchange of body fluids from an infected person to another person. Thus, contact with the body fluids of an AIDS infected person must be avoided. As noted above, if an introducer needle has been used to place a catheter in a blood vessel of an AIDS infected person, the introducer needle, via its sharp distal tip, is a vehicle for the transmission of the disease. Although clinicians are aware of the need to properly handle blood contaminated sharps, unfortunately, in certain medical environments such as emergency situations or as a result of inattention or neglect, needlesticks with a blood contaminated sharp still occur.
As a result of the problem of accidental needlesticks by blood contaminated sharps, various needle shields have been developed. Such devices are disclosed in, for example, U.S. Pat. Nos. 5,601,536 and 4,952,207. Generally, such needle shields rely on movement and interaction between a projection or fingers and a notch.
It would be desirable to provide a capture and shielding arrangement having an improved capture mechanism.